Composition for and method of applying ceramic color



United States Patent 3,089,782 (IOMPOSITION FOR AND METHOD OF APPLYING CERAMIC COLQR Donald R. Bush, Parma, Ohio, and Thomas E. Howarth and Roy Lawrence, (Oakville, Ontario, Canada, assignors to Ferro Corporation, Cleveland, Ohio No Drawing. Filed May 27, 1960, Ser. No. 32,140

15 Claims. (Cl. 117-38) This invention deals generally with color compositions and more particularly with a thermoplastic vehicle for applying same to articles of manufacture.

In the decoration of certain surfaces, such as ceramic and porcelain enamel, by far the most popular and eflicient method yet found has been the so-called silk screen stencil method whereby a pigment and flux are squeegeed, dispersed in a suitable vehicle, through a fine mesh screen, stenciled to produce the desired pattern, and subsequently subjecting the aforementioned pigment-flux dispersion to a firing operation which drives off the organic constituents of the vehicle, and at the same time fusing the flux thus binding the pigment in a vitreous bond to the surface to be decorated.

In the glass container industry especially, it is frequently desirable to produce multicolored designs which may consist of six, seven or even eight different colors. In this contex color refers to the pigment-fiux-vehicle dispersion, as opposed to pigment, one of the color constituents.

During the early development of the silk screen process, in order to produce successfully a multi-colored design, the vehicles of that time being of a slow-drying type, it was necessary to screen the first color onto the article to be decorated, send the article through a drying operation to solidify and harden the vehicle, return the article for the application of the next color, etc., thus interposing a drying operation between successive applications of each color in order to prevent smearing and bleeding of one color into another. When all the colors had been thus applied, with their respective vehicles dryer-hardened, the article to be decorated was subjected to a temperature, usually above 800 F., which served to completely burn off and volatilize the vehicle and at the same time fuse the flux, thus fixing the pigment to the surface of the article to be decorated in a vitreous bond in a pattern predetermined by the design of the silk screen, or such other suitable stencil through which the colors had been applied.

Later, as the art developed, improved, thermo-fluid vehicles were developed which were fluid at elevated tem peratures, but which quickly solidified at normal room temperature. Utilizing such vehicles, a suitably heated silk screen stencil, actually composed of stainless steel, kept the combination ceramic pigment-flux-vehicle dispersion in a fluid state, said combination solidifying within a matter of seconds however after screening onto the relatively cool surface of a glass or porcelain enameled article. Immediately after completion of the color application steps, the decorated article was subjected to a firing operation at a temperature, usually above 800 F., at which the organic, thermo-fluid vehicle was completely oxidized and volatilized, and the flux fused, thus fixing the pigment to the stmface of the article to be decorated in a vitreous bond in a pattern predetermined by the design of the silk screen, or other suitable stencil through which the colors had been applied.

The rapid solidification feature of the thermo-fiuid vehicles thus obviated the need for a time-consuming and expensive drying operation between successive color applications as had heretofore been necessary.

Varieties of the earlier thermo-fiuid vehicles are best typified by the teachings of United States Patent Nos. 2,607,701, 2,607,702, 2,682,480, 2,807,555, and 2,842,454.

However, although the vehicles described by the aforementioned patents represented a vast improvement over previous methods, it was found that there were still practical limitations to be overcome.

While the newly developed thermo-fiuid vehicles permitted, multiple, successive application of colors without an intermediate drying step, it was found that in designs which required more than 3 or 4 different colors, hence more than 3 or 4 successive screening applications over the same general area, the firing operation during which the vol atil-ization of the thermo-fluid vehicle took place, and the flux was fused, usually at a temperature in excess of 800 F., resulted in a highly undesirable sagging or creeping of one color into the area occupied by other colors. Thus, if it were necessary to set up an eight color design, 4 of the colors could be quickly screened, but then a firing operation would be necessary before the remaining 4 colors could be screened into place. Thus, at least 2 firing operations were necessary in order to achieve a clear-cut, eight color design. And, utilizing the intermediate firing operation as described above, excessive sagging would still frequently be noticeable in the finished piece. The purpose of the intermediate firing operation as described above was simply to fuse the flux, and thus densify the first series of colors which had the effect of minimizing sagging in subsequently applied colors, although again, such sagging was still noticeable, only not to such a degree. The reason for sagging was probably due to the fact that the previous vehicles retained no body at the higher temperatures and readily flowed down the vertical sides of the articles to be deco rated during the heating-up cycle of the firing operation, and before the vehicle was oxidized and driven off.

It was further found that previous thermo-flu-id vehicles used for this purpose had a tendency, due to insufiicient fluidity at the screen temperature, to promote tiny pinholes in the design during the screening operation, which pinholes were later enlarged during the firing operation thus resulting in a commercially undesirable appearance of the design. Furthermore, this somewhat porous structure, characterized by numerous tiny pinholes, tended to promote bleeding of subsequently screened colors into the base colors during the few seconds required for the subsequently screened colors to solidify following application to the article to be decorated.

We have discovered novel color compositions which overcome the difficulties encountered in previous thermofluid compositions, which permit up to 8 color applica tions, requiring only one firing operation, during which firing operation there is no sagging or displacement of any of the colors into areas occupied by other colors. Furthermore, our color compositions exhibit physical characteristics such that even though the vehicle quickly solidifies upon coming in contact with a room temperature surface to be decorated, it is still sufficiently fluid, at the instant of application, to flow evenly and completely into the area outlined by the stencil, filling all minute voids and eliminating any pinholes or porosity during that brief period before it sets up, or solidifies, by contact with the relatively cool surface to be decorated.

These characteristics of novel vehicle composition enable the same to be adapted readily to the process of multicolor screening on bisque, or dry unfired, ceramic surfaces such as unfired ceramic glazes and unfired porcelain enamels.

It is therefore an object of this invention to provide a thermo-fiuid vehicle for applying ceramic colors which need not be subjected to a drying operation intermediate the application of successive colors in multi-colored work.

A further object of this invention is to provide a thermo-fiuid vehicle which may be used to screen up to eight different colors, in eight successive screening operations, without necessitating a firing operation intermediate the application of any of the colors.

Another object of this invention is to minimize sagging or creeping of screened, ceramic colors during the fusion of said ceramic colors to the surface to be decorated.

Yet another object of this invention is to provide a thermo-fiuid vehicle for applying ceramic color to a ceramic surface, which vehicle can be used without holes and minute voids usually found in screened colors.

Another object of this invention is to eliminate a drying operation intermediate successive applications of color in multicolor decoration by the silk screen, or other stencil process.

Summarizing our invention, we produce a color comprising a ceramic flux which is fusible at temperatures of about 800 F. or above, any one of a number of inorganic ceramic pigments, and a thermo-fiuid vehicle consisting essentially of a wax and a thermo-plastic resin proportioned in such a way as to become a quick-hardening solid when exposed to temperatures less than 100 F. from its fluid state, said vehicle being fluid at between about 100 F. and 500 F. and which is characterized by a complete volatilization, without carbonaceous residue, at temperatures in excess of 800 F.

Thus, the flux and pigment which are thoroughly dispersed in the fiowable heated thermo-fiuid vehicle, may be spread on a receiving surface from a heated reservoir of the vehicle maintained at temperatures between 100 F. and 500 F. As the hot, fluid fiux-pigment vehicle dispersion comes in contact with a relatively cool surface whose temperature is less than 100 F., said vehicle solidifies in a matter of seconds, thus fixing the color to the surface according to a pre-determined pattern, depending upon whether a silk screen, out stencil, etc., is used.

Immediately following such application, another color may obviously be applied over the same general area occupied by the first color without fear of smearing said first color. As previously indicated, surprisingly, even seven or eight different color applications may be made to the same general area.

A piece to be decorated is then subjected to a temperature in excess of 800 P. which volatilizes and completely removes all traces of the thermo-fiuid vehicle, and at the same time fuses the ceramic flux thus fixing the pigment in a vitreous bond to the surface to be decorated.

Previous thermo-fiuid vehicles such as those taught by United States Patent No. 2,682,480 required a minimum of three components in order to achieve a proper thermofluid vehicle, such components falling generally into the classification of a wax, a thermo-plastic resin, and a solvent for said resin. Through proper reproportioning of components falling in the broad classification of waxes or thermo-plastic resins, we have completely eliminated the solvent previously required and in so doing have achieved improved and unexpected results in the field of color decoration.

Further, the greatly improved results were obtained without the use of certain materials thought necessary for such vehicles. Among the materials thought necessary are certain oils, such as tall oil, and stearyl acid phosphate. We have found the use of such compounds objectionable as they tend to aggravate sagging during the firing operation and further hinder achievement of a sharp, nearly instantaneous pre-selected solidification point. All the components of our novel vehicle are solids at temperatures below F.

In the practice of our invention, we have found that any number of well known ceramic fluxes, of a vitreous nature, may be utilized to effect the vitreous bond of the finished design to the decorated surface. Depending upon the temperature at which the piece to be decorated will be fired, the fiux fusion temperature may vary considerably. For example, in the decoration of glass bottles, a decorating lehr temperature of 1200 P. will obviously require a flux which will fuse at, or preferably below 1200 F., inasmuch as the combined pigment has a refractory influence such that the flux should have a fusion temperature several degrees below the maximum indicated temperature of the decorating lehr. Normally, a flux that has a fusion temperature above 800 F. can be utilized for most glass decorating purposes.

Normally, the pigment/vehicle ratio is about 3.0 to 4.0 to l to get the best results although if the thermofiuid vehicle is slightly thin, a ratio of up to 4.5 to l or even higher may be employed advantageously.

In the field or decoration of porcelain enamel, the flux may have to be compounded so that its fusion temperature will be compatible with porcelain enamel having a normal firing temperature of 1500 F.

The ceramic color used in the practice of this invention may be any of the well known inorganic coloring oxides and the color oxide may either be smelted into the flux, or the flux and pigment, may be individually milled to sub-sieve fineness, on the order of about 1 to 3 microns for subsequent incorporation and dispersion with a thermo-fiuid vehicle.

At any rate, both the flux and pigment components of this invention are well known in the art and are of conventional manufacture and composition. The novel aspect of our invention lying in the combination of either a pigment alone, or a pigment and a fiux, with a thermofiuid vehicle of novel composition, for achieving a new, distinct and novel result.

We have found that a Wide variety of individual waxes, or combinations of waxes, may be used successfully in any one or several of the basic compositions which form the basis for this invention. There are certain limitations however and the waxes used in the practice of our invention must have physical characteristics such that they will completely volatilize and burn out at temperatures in excess of 800 F. with no trace of carbonaceous or inorganic residue. Although not absolutely essential, we have also found that waxes, or wax-like materials, having a melting point in excess of 100 F. are most desirable in our preferred embodiment.

Examples of the waxy materials which provide the excellent thermo-fluid vehicles Without the use of a solvent are a substantially straight chain alcohol having 12 to 20 carbon atoms such as stearyl alcohol, palmitic alcohol, cetyl alcohol and lauryl alcohol; a substantially straight chain fatty acid having 12 to 20 carbon atoms such as stearic acid, palmitic acid, and lauric acid; an amide of an aliphatic hydrocarbon having 16 to 20 carbon atoms such as hexadecane, octadecane and octadecene and including Armid HT, a wax sold by Armour & Company which is believed to be composed by amides of hexadecane, octadecane and octadecene having a melting point of about 97 C.; and a polyalkylene ether glycol having a molecular weight of about 2000 to 6000 in which the alkylene groups have 2 to 3 carbon atoms, and mixtures thereof and including Carbowax 4000 a polyethylene ether glycol having a molecular weight of about 4000 sold by Union Carbide Corporation.

Of the above mentioned waxy materials, by far the best results are obtained using stearyl alcohol and palmitic acid either alone or together and preferably with about 3 to 5 parts of a polyethylene ether glycol having a molecular weight of 3000 to 5000. When palmitic acid is used the best range thereof is about 87 to 89' parts, this being slightly higher than the optimum range of 81 to 83 parts for stearyl alcohol since the palmitic acid does not work up quite as easily in the formulations as does stearyl alcohol.

In a like manner we have also found that certain thermoplastic resins will provide us with excellent results and these are listed below along with some of the details of their physical and chemical properties. As is true of the waxes, and wax-like materials, the resins which go to make up the compositions of this invention must burn out cleanly and completely at temperatures in excess of 800 F. and leave no objectionable carbonaceous or inorganic residue which would detract from the appearance of the fired color. Suitable thermo-plastic resins are rosin, limed rosin, hydrogenated rosin, limed hydrogenated rosin, polyhydric alcohol ester of hydrogenated rosin Poly pale rosin, limed Poly pale rosin and ethyl cellulose having a viscosity of at least 100 centipoises per second in a 5% solution at 25 C. Hercules (Hercules Powder Co. Test E 80-817 Ethyl Cellulose, 6-26-36; Rev. '8-2-38 and 4-22-59), and mixtures thereof in which any ethyl cellulose present is present in amounts less than about parts by weight.

Of the above mentioned resins, the Poly pale resin is preferred. Poly pale is sold by the Hercules Powder Company of Wilmington, Delaware, and is prepared by polymerizing rosin. The best results are obtained using the Poly pale resin in combination with stearyl alcohol and/ or palmitic acid, along with preferably 3 to 5' parts by weight of ethyl cellulose having a viscosity of at least about 100 centipoises in a 5% solution. The ethyl cellulose should also have preferably an ethoxyl content of about 48 to 49.5%.

The best formulation with palmitic acid contains about 86 to 90 parts of palmitic acid and about 4 to 6 parts of Poly pale rosin, along with about 2 to 5 parts each of Carbowax 4000 and ethyl cellulose.

Thus, the preferred thermo-fluid vehicle of the present invention comprises 80 to 90 parts by weight of stearyl alcohol and/or palmitic acid and 10 to 20 parts by Weight of Poly pale resin with the amounts of the above preferred Waxes and resin, respectively, being cut down preferably by 3 to 5 parts of polyethylene ether glycol and 3 to 5 parts of ethyl cellulose.

PROCEDURE In all the examples that follow, certain preparation procedures were followed uniformly throughout. In every example, the glass flux and ceramic pigment were added individually, that is, the ceramic pigment Was not fused into the flux beforehand.

In each example, the wax and thermo-plastic resin components were introduced along with the indicated amounts,by weight, of ceramic pigment and flux, into a suitable mixer wherein the temperature of the mix could be controlled within relatively narrow limits.

The wax and resin of each example, were introduced into a suitable mixer whose temperature was controllable within relatively close tolerances, said wax and resin components being mixed for 2 hours at 210 F. to a homogeneous fluid. After mixing the vehicle components for 2 hours, the glass flux and pigment were added in the amounts indicated, both the flux and pigment being of a particle size substantially finer than the decorating screen through which they ultimately would pass.

Mixing was continued for another hour after which the fluid contents of the mixer comprising the dispersion of ceramic flux and pigment in the wax-thermo-plastic resin vehicle was poured through a conventional 3 roll hot mill, the temperature of the rolls being maintained at 165 F. One pass was sufficient through the 3 roll mill to insure complete dispersion of the flux and pigment Palmitio Acid throughout the color, and to eliminate any lumps or agglomerations which may have formed in the hot mixer. From the 3 roll hot mill, the color was permitted to flow into stainless steel pans where it solidified, later being broken into pieces approximately 2 inches in diameter suitable for feeding a heated decorating screen or stencil.

For printing, a conventional silk screen composed of approximately 165 mesh stainless steel, the Wire of which is approximately 0.040 inch in diameter, was used. Controlled current was fed through the mesh of the screen in order to maintain the desired printing temperature, and the screen itself was insulated from the supporting superstructure for protection of the operator.

As will be seen from the examples which follow, the printing temperature, or temperature of the silk screen, is usually adjusted to be from approximately 10 F. to 15 F. above the freezing point of the vehicle.

In all cases, conventional methods, well known in the art, were used for decoration of the pieces described in the examples whereby the screen was heated as indicated, brought into close proximity to the surface to be decorated, a pass was made over the screen stencil with a rubber squeegee depositing a thin layer of color onto the relatively cool surface of the glass, thus quickly solidifying the vehicle and fixing the color to the glass surface in accordance with the stencil pattern of the silk screen.

In all the examples, the glass pieces were placed in a conventional lehr and fired at a temperature of 1200 F. which completely burned olf the vehicle and fused the ceramic flux.

In ceramic colors, the flux and pigment are normally present in a ratio of from about :5 to about 70:30, by weight. In the examples listed below, the ratio of flux to pigment was maintained at 90: 10.

The ratio of the combination of pigment and flux to thermo-fluid vehicle ranges from 3:1 to 4.521, the exact ratios being shown in Table II for each example.

In order to induce sagging for the most rigorous test, all glass test pieces were placed inthe firing lehr in such a way that the decorated surface was vertical. The reason for this being that, inasmuch as our novel invention overcomes sagging in successive color applications, we Wished our examples subjected to the worst test conditions to better illustrate the novelty and utility of our invention,

Examples As previously indicated in the procedural stepsoutlined above, a series of thermo-fluid vehicles were prepared, mixed with a pigment which included a ceramic flux and an inorganic colorant, and used to decorate a glass plate. The particular vehicle used and the pigment/ vehicle ratio by weight are listed below in Table I. In all the test runs, the vehicle/pigment mixture was applied by making one pass with a screen temperature at F., followed immediately by seven consecutive passes. The colors were fired at 1200 F. and preheated in each case at about 700 to 800 F. long enough to burn away all the combustible hydrocarbon and organic material. The vehicle/pigment mixture was applied at the rate of 0.4 gr-am or 0.08 gram/square inch of glass surface.

TABLE I A B o D E F o H Lorol #28 Foslo Wood Rosin. Ethyl Cellulose N-20 Carbowax #4000..." Stearic-Acid Poly Pale Rosin Staybelite Rosin.

Melting Pt, F

Ratio, Pigment.

Vehicle by Wt.

aosazsa In the above table, Lorol #28 is stearyl alcohol sold by the Polychemicals Department of E. I. du Pont de Nemours and C0,, Incorporated, Wilmington, Delaware. Carbowax 4000 is a polyethylene ether glycol having a molecular Weight of about 4000 sold by the Union Carbide Chemicals Company, a division of Union Carbide Corporation.

Poly pale rosin is a hard, brittle polymerized rosin having a color grad of N-WG, melting at 208-217 F., and sold by the Hercules Powder Company. The Poly pale resins is prepared by polymerizing the unsaturated resin acids contained in rosinnarnely, pimeric and abietic acids. A full description of Poly pale resins is found in the second edition-July l942-bulletin issued by the Naval Stores Department of the Hercules Powder Company of Wilmington, Delaware.

Fosfo wood rosin is a limed Wood rosin containing about 4.5% calcium hydroxide, having a ball and ring melting of 230 R, an acid number of 88 and sold by Newport Industries Company, New York, New York.

Further referring to the ingredients in Table I, Lorol #24 is cetyl alcohol sold by Du Pont. Stabelite is a hard, brittle hydrogenated rosin sold by the Hercules Powder Company.

As seen from the ingredients used in Table I, in Example A, the eighty-two parts by weight of Lorol #28 (stearyl alcohol) was mixed with 10 parts by weight of wood rosin, parts of ethyl cellulose having a viscosity of 200 centipoises, and 3 parts of Carbowax #4000. A color material was then made by mixing 3.4 parts by weight of pigment for each one part by weight of the above described thermo-iluid vehicle. The mixing was accomplished at 210 F. for a time of one hour. The freezing point of the resultant color was 125 F. and the printing temperature employed was 135 F.

Two thin glass test plates, as previously indicated, were used in these trials, two plates being used for white pigment and the other two for red pigment. Each plate received eight successive applications, one following the other in a matter of seconds with no intermediate drying step. The plates were fired, resulting in a pleasing glossy surface with no evidence of sagging.

The color mixtures made from pigments and the ther mo-fiuid vehicles A, B, C, D, E, F, G, and H also were outstanding and showed no signs of sagging even after eight coats.

Using the procedures set forth to the example shown in Table I, another series of thermo-fiuid vehicles were prepared, mixed with pigment, and used to decorate a glass plate. The pigment/vehicle ratio, the total weight percent of wax, and the total wax percent used are shown in Table II.

The type of wax including any Carbowax 4000 used and the type of thermo-plastic resin used are shown in TABLE III Wax-like Material 'Ihermo-plastic resin Thermo- Fluid Vehicle Parts of Parts of Type of Wax Carbowax Type of Resin ethyl 4000 Cellulose J stearyl alcohol. 3 5%ll1m0d Poly 5 pa e. K chlorowax #70. Poly pale... ....i 5 L parailln hydrogenated rosin. M do do N palmitic aeid 3 Poly pale 4 O stearyl alcohol. 3 glyceryl ester of 5 hydrogenated rosin. P do 3 Poly pale Q cetyl alcohol-60 Armid HT-40. R .c stearyl aleohoL. 50 S eetyl alcohol... 3 Po y pale T stcaryl alcohol. 3 do U do 3 approx. 5% lirned wood rosin V do 3 approx. 7% luned wood rosin. W stearic acid 3 llmed Poly pale... X stearyl alcohol. 5 Y Armitl IIT 3 In the above table, the majority of the color mixtures were excellent, there being no sagging even after eight coats. However, compositions K, L and M were unsatisfactory. The former composition used chlorinated hydrocarbon wax; the latter two used paraifin wax. Composition K was too difficult to melt while compositions L and M saggcd.

Other unsatisfactory compositions were Q and R. The print was blurred and smeared in Q while the pigment/ vehicle mixture R was not easily workable and the vehicle clogged the screen.

Vehicle composition P represents one of the best vehicles. When some of the particular ingredients are substituted for, a degradation may result. For instance, when 10 parts of the glyceryl ester of hydrogenated rosin are substituted for the 10 parts of Poly pale resin, some sagging is encountered as was shown by vehicle 0. However, surprisingly, the glyceryl ester of hydrogenated rosin can be used in a good vehicle by mixing 50 parts of stearyl alcohol and 45 parts of polyethylene ether glycol having a molecular weight of about 4000, with about 3 to 8 and, preferably, 5 parts by weight of the above named glyceryl ester.

Vehicle X illustrates some of the degradation in properties as the ingredients reach the limits of their tolerable ranges. While satisfactory for some purposes, vehicle X exhibited a slight tearing and slight sagging on the eighth coat. Generally, the addition of a small amount of ethyl cellulose both as a resin and a bodying agent helps eliminate tearing.

Further commenting on the compositions of Table II, vehicle T illustrates a good vehicle made without the use of ethyl cellulose as part of the resin component. The amount of pigment used was slightly higher than some of the other formulations to help thicken the pigment-vehicle mixture.

Various modifications may be made in the compositions of the present invention without departing from the spirit or scope thereof and it is to be understood that we limit ourselves only as defined in the appended claims.

What is claimed is:

1. A thermo-fluid vehicle for application of glass colors to a base on which they will subsequently be fired, said vehicle consisting essentially of (1) about 70 to parts by weight of a wax-like material selected from a member of a group consisting of (a) a substantially straight chain fatty acid having from 12 to .20 carbon atoms, (b) a substantially straight chain fatty alcohol having from 12 to 20 carbon atoms, (0) an amide of an aliphatic hydrocarbon having 16 to 20 carbon atoms and (d) a poly alkylene ether glycol having a molecular weight of about 2000 to 6000 in which the alkylene groups have 2 to 3 carbon atoms, and mixtures thereof, any poly alkylene ether glycol present being in the amount of less than 50 parts by weight and in combination with at least one of the above named group of a, b, and c; and (2) about 5 to 30 parts by weight of a thermoplastic resin selected from a member of a group consisting of rosin, limed rosin, hydrogenated rosin, limed hydrogenated rosin, polyhydric alcohol ester of hydrogenated rosin, a hard "brittle resin that is a polymerization product of rosin and has a melting point of about 208 to 217 F., a reaction product of lime and said brittle resin having a melting point of about 208 to 217 F. and ethyl cellulose having a viscosity of at least 100 centipoises per second in a 5% solution at 25 C. Hercules Powder Company Test E 80-8b, and mixtures thereof in which any ethyl cellulose present is present in amounts less than about 10 parts by weight.

.2. A thermo-fluid vehicle for application of glass colors to a base on which they will subsequently be fired, said vehicle consisting essentially of 1) about 82 to 88 parts by weight of a wax-like material selected from a member of a group consisting of (a) a substantially straight chain fatty acid having from 12 to 20 carbon atoms, (b) a substantially straight chain fatty alcohol having from 12 to 20 carbon atoms, an amide of an aliphatic hydrocarbon having 16 to 20 carbon atoms and (d) a poly alkylene ether glycol having a molecular weight of about 2000 to 6000 in which the alkylene groups have 2 to 3 carbon atoms, and mixtures thereof, any poly alkylene ether glycol present being in the amount of less than 30 parts by weight and in combination with at least one of the above named group of a, b, and c; and (2) about 12 to 1 8 parts by weight of a thenno-plastic resin selected from a member of a group consisting of rosin, limed rosin, hydrogenated rosin, limed hydrogenated rosin. polyhydric alcohol ester of hydrogenated rosin, a hard brittle resin that is a polymerization product of rosin and has a'melting point of about 208 to 217 F., a reaction product of lime and said brittle resin having a melting point of about 208 to 217 F. and ethyl cellulose having a viscosity of at least 100 centipoises per second in a 5% solution 25 C. Hercules Powder Company Test E 80-8b, and mixtures thereof in which any ethyl cellulose present is present in amounts less than about parts by weight.

3. A thermo-fiuid vehicle for application of glass colors to a base on which they will subsequently be fired, said vehicle consisting essentially of 82 to 85 parts by weight of stearyl alcohol, 1 to 5 parts by weight of poly ethylene ether glycol having a molecular weight of about 1000 to 6000, 2 to 7 parts by weight of ethyl cellulose, and 8 to parts by weight of wood rosin.

4. A thermo-fluid vehicle for application of glass colors to a base on which they will subsequently be fired, said vehicle consisting essentially of 82 to 85 parts by weight of stearyl alcohol, 1 to 5 parts by weight of polyethylene ether glycol having a molecular weight of about 1000 to 6000, 2 to 7 parts by weight of ethyl cellulose, and 8 to 15 parts by weight of limed rosin.

5. A thermo-fluid vehicle for application of glass colors to a base on which they will subsequently be fired, said vehicle consisting essentially of 82 to 85 parts by weight of stearyl alcohol, 1 to 5 parts by weight of poly ethylene ether glycol having a molecular weight of about 1000 to 6000, 2 to 7 parts by weight of ethyl cellulose, and 8 to 15 parts by weight of hydrogenated rosm.

6. A thermo-fluid vehicle for application of glass colors to a base on which they will subsequently be fired, said vehicle consisting essentially of 82 to 85 parts by weight of stearyl alcohol, 1 to 5 parts by weight of poly ethylene ether glycol having a molecular weight of about 1000 to 6000, 2 to 7 parts by weight of ethyl cellulose,

10 and 8 to 15 parts by weight of a hard brittle resin obtained by polymerizing rosin, said resin having a melting point of about 208 to 217 F.

7. A thermo-fiuid Vehicle for application of glass colors to a base on which they will subsequently be fired, said vehicle consisting essentially of about 70 to 84 parts by weightof stearyl acid, 3 to 5 parts by weight of a poly ethylene glycol having a molecular Weight of about 3000 to 5000, about 4 to 6 parts by weight of ethyl cellulose, and about 16 to 30 parts by weight of a thermoplastic resin selected from a member of the group consisting of rosin, limed rosin, hydrogenated rosin, limed hydrogenated rosin, a poly hydric alcohol ester of hydrogenated rosin, a hard brittle resin that is a polymerization product of rosin and has a melting point of about 208 to 217 F., a reaction product of lime and said brittle resin having a melting point of about 208 to 217 F. and ethyl cellulose.

8. A thermo-fluid vehicle for application of glass colors to a base on which they will subsequently be fired, said vehicle consisting essentially of about 82 to 88 parts by weight of a wax-like material having a chain consisting of about 12 to 20 carbon atoms as the main chain, and about 12 to 18 parts by weight of a thermoplastic resin comprising rosin.

9. A thermo-fluid vehicle for application of glass colors to a base on which they will subsequently be fired, said vehicle consisting essentially of about 70 to 84 parts by weight of stearyl alcohol, 3 to 5 parts by weight of a polyethylene glycol having a molecular weight of about 3000 to 5000, about 4 to 6 parts by weight of ethyl cellulose, and about 16 to 30 parts by weight of a thermoplastic resin selected from a member of the group consisting of rosin, limed rosin, hydrogenated rosin, limed hydrogenated rosin, a poly hydric alcohol ester of hydrogenated rosin, a hard brittle resin that is a polymerization product of rosin and has a melting point of about 208 to 217 F., a reaction product of lime and said brittle resin having a melting point of about 208 to 217 F. and ethyl cellulose.

10. A thermo-fluid vehicle for application of glass colors to a base on which they will subsequently be fired, said vehicle consisting essentially of about 86 to 90 parts by weight of palmitic acid ,2 to 5 parts by weight of poly ethylene glycol having a molecular weight of about 3000 to 5000, about 2 to 5 parts by weight of ethyl cellulose, and about 4 to 6 parts of a hard brittle resin obtained by polymerizing rosin, said resin having a melting point of about 208 to 217 F.

A method of applying glass colors to a base comprising the steps of applying a first coat to said base through a screen stencil a melted glass color-containing composition that comprises a ceramic flux carrying a ceramic color dispersed in a thermo-fluid vehicle consisting essentially of (1) about 70 to parts by Weight of a wax-like material selected from a member of a group consisting of (a) a substantially straight chain fatty acid havmg from 12 to 20 carbon atoms, (b) a substantially straight chain fatty alcohol having from 12 to 20 carbon atoms, (c) an amide of an aliphatic hydrocarbon havmg 16 to 20 carbon atoms and (d) a poly alkylene ether glycol having a molecular weight of about 2000 to 6000 in which the alkylene groups have 2 to 3 carbon atoms, and mixtures thereof, any poly alkylene ether glycol present being in the amount of less than 50 parts by weight and in combination with at least one of the above named group of a, b, and c; and (2) about 15 to 30 parts by weight of a thermoplastic resin selected from a member of a group consisting of rosin, limed rosin, hydrogenated rosin, limed hydrogenated rosin, polyhydric alcohol ester of hydrogenated rosin, a hard brittle resin that is a polymerization product of rosin and has a melting point of about 208 to 217 F., a reaction product of lime and said brittle resin having a melting point of about 208 to 217 F. and ethyl cellulose having a viscosity of at least 100 centipoises per second in a solution at 25 C. Hercules Powder Company Test E 80-8b, and mixtures thereof in which any ethyl cellulose present is present in amounts less than about parts by weight, applying a plurality of at least three coats over said first coat with out intermediate heating steps, and thereafter heating the base with the applied coats to leave the glass carrying color on the base and fused thereto.

12. A method as defined in claim 11 in which the thermoplastic resin is a wood product resin.

13. A method of applying glass colors to a base characterized by a reduced tendency toward pinholing in said colors, comprising the steps of applying a first coat to said base through a screen stencil a melted glass colorcontaining composition that comprises a ceramic flux carrying a ceramic color dispersed in a thermo-fiuid vehicle consisting essentially of (1) about 70 to 95 parts by weight of a wax-like material selected from a member of a group consisting of (a) a substantially straight chain fatty acid having from 12 to carbon atoms, (b) a substantially straight chain fatty alcohol having from 12 to 20 carbon atoms, (c) an amide of an aliphatic hydrocarbon having 16 to 20 carbon atoms and (d) a poly alkylene ether glycol having a molecular weight of about 2000 to 6000 in which the alkylene groups have 2 to 3 carbon atoms, and mixtures thereof, any poly alkylene ether glycol present being in the amount of less than 50 parts by weight and in combination with at least one of the above named group of a, b, and c; and (2) about 15 to 30 parts by weight of a thermoplastic resin selected from a member of a group consisting of rosin, limed rosin, hydrogenated rosin, limed hydrogenated rosin, polyhydric alcohol ester of hydrogenated rosin, a hard brittle resin that is a polymerization product of rosin and has a melting point of about 208 to 217 F., a reaction product of lime and said brittle resin having a melting point of about 208 to 217 F. and ethyl cellulose, and mixtures thereof in which any ethyl cellulose present is present in amounts less than about 10 parts by weight, applying a plurality of from about three to seven coats over said first coat without intermediate heating steps and thereafter heating the base with the applied coats to leave the glass carrying color on the base and fused thereto with a minimum of pinholing.

14. A composition consisting essentially of about 82 parts by weight of stearyl alcohol, about 3 parts by weight of a polyethylene ether glycol having a molecular weight of about 4000, about 5 parts by weight of ethyl cellulose, and about 10 parts by weight of a hard brittle resin comprising polymerized rosin and having a melting point of about 208 to 217 F.

15. A method of applying glass colors to a base characterized by a reduced tendency toward pinholing in said colors, comprising the steps of applying a first coat to said base through a screen stencil a melted glass colorcontaining composition that comprises a ceramic flux carrying a ceramic color dispersed in a thermo-fluid vehicle consisting essentially of about 82 parts by weight of stearyl alcohol, about 3 parts by weight of a polyethylene ether glycol having a molecular weight of about 4000, about 5 parts by weight of ethyl cellulose, and about 10 parts by weight of a hard brittle resin comprising polymerized rosin and having a melting point of about 208 to 217 F., applying a plurality of from about three to seven coats over said first coat without intermediate heating steps and thereafter heating the base with the applied coats to leave the glass carrying color on the base and fused thereto with a minimum of pinholing.

References Cited in the file of this patent UNITED STATES PATENTS 2,607,701 lessen Aug. 19, 1952 2,682,480 Andrews June 29, 1954 2,872,326 Morris Feb. 3, 1959 OTHER REFERENCES Chemical and Engineering News, February 10, 1945, page 247 et a1. 

11. A METHOD OF APPLYING GLASS COLORS TO A BASE COMPRISING THE STEPS OF APPLYING A FIRST COAT TO SAID BASE THROUGH A SCREEN STENCIL A MELTED GLASS COLOR-CONTAINING COMPOSITION THAT COMPRISES A CERAMIC FLUX CARRYING A CERAMIC COLOR DISPERSED IN A THERMO-FLUID VEHICLE CONSISTING ESSENTIALLY OF (1) ABOUT 70 TO 95 PARTS BY WEIGHT OF A WAX-LIKE MATERIAL SELECTED FROM MEMBER OF A GROUP CONSISTING OF (A) A SUBSTANTIALLY STRAIGHT CHAIN FATTY ACID HAVING FROM 12 TO 20 CARBON ATOMS, (B) A SUBSTANTIALLY STRAIGHT CHAIN FATTY ALCOHOL HAVING FROM 12 TO 20 CARBON ATOMS, (C) AN AMIDE OF AN ALIPHATIC HYDROCARBON HAVING 16 TO 20 CARBON ATOMS AND (D) A POLY ALKYLENE ETHER GLYCOL HAVING A MOLECULAR WEIGHT OF ABOUT 2000 TO 6000 IN WHICH THE ALKYLENE GROUPS HAVE 2 TO 3 CARBON ATOMS AND MIXTURES THEREOF, ANY POLY ALKYLENE ETHER GLYCOL PRESENT BEING IN THE AMOUNT OF LESS THAN 50 PARTS BY WEIGHT AND IN COMBINATION WITH AT LEAST ONE OF THE ABOVE NAMED GROUP OF A, B AND C; AND (2) ABOUT 15 TO 30 PARTS BY WEIGHT OF A THERMOPLASTIC RESIN SELECTED FROM A MEMBER OF A GROUP CONSISTING OF ROSIN, LIMED ROSIN, HYDROGENATED ROSIN, LIMED HYDROGENATED ROSIN, POLYHYDRIC ALCOHOL ESTER OF HYDROGENATED ROSIN, A HARD BRITTLE RESIN THAT IS A POLYMERIZATION PRODUCT OF ROSIN AND HAS A MELTING POINT OF ABOUT 208 TO 217*F., A REACTION PRODUCT OF LIME AND SAID BRITTLE RESIN HAVING A MELTING POINT OF ABOUT 208 TO 217*F. AND EHTYL CELLULOSE HAVING A VISCOSITY OF AT LEAST 100 CETIPOISES PER SECOND IN A 5% SOLUTION AT 25*C. HERCULES POWDER COMPANY TEST E 80-8B, AND MIXTURES THEREOF IN WHICH ANY ETHYL CELLULOSE PRESENT IS PRESENT IN AMOUNTS LESS THAN ABOUT 10 PARTS BY WEIGHT, APPLYING A PLURALITY OF AT LEAST THREE COATS OVER SAID FIRST COAT WITH OUT INTERMEDIATE HEATING STEPS, AND THEREAFTER HEATING THE BASE WITH THE APPLIED COATS TO LEAVE THE GLASS CARRYING COLOR ON THE BASE AND FUSED THERETO. 